<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      body {
        background: linear-gradient(-45deg, #ee7752, #757ecb, #23a6d5, #23d5ab);
        background-size: 400% 400%;
        animation: gradient 15s ease infinite;
        height: 100vh;
      }

      @keyframes gradient {
        0% {
          background-position: 0% 50%;
        }
        50% {
          background-position: 100% 50%;
        }
        100% {
          background-position: 0% 50%;
        }
      }
    </style>
  </head>
  <body></body>
</html>
